P30x Codes and Cylinders

[Joshua Logsdon]

I’ve been having trouble finding a solid answer to P30x codes, cylinders, and firing orders. For example, on a 6-cylinder engine with a P304 code saying a cylinder #4 misfire, I’ve seen information that it’s the 4th cylinder in the firing order, which may not actually be cylinder #4. So if the firing order is 1-4-2-5-3-6, I would think that it’s really cylinder #5 to investigate because it’s the 4th cylinder in the firing order. But I see people in YouTube videos going straight for cylinder #4 (understandably because that’s what the code says) and not considering the firing order. Can anyone shed any light on this for me?

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[Richard Kirshy]

the 4th cylinder in the firing order, which may not actually be cylinder #4. So if the firing order is 1-4-2-5-3-6, I would think that it’s really cylinder #5 to investigate because it’s the 4th cylinder
Ummmm…no.
The misfire code directs you to the actual cylinder, not the rotational count of the firing order.
Going by your interpretation the OBD diagnostics would require several standards then according to ignition firing orders instead of physical cylinder.

[Joshua Logsdon]

Thank you! Information like below was throwing me off when it talked about the code digits “correspond to the cylinder number in the engine’s firing order”. I don’t know if they are saying it correctly and it’s just the way I’m interpreting the info, but it had me thinking I needed to know the firing order to use the code and track down the actual cylinder. I’ll go by the code digit telling me which cylinder it is and then just making sure I know which cylinder is that digit.

The last two digits in the misfire code will tell you which cylinder or cylinders are misfiring. The digits correspond to the cylinder number in the engine’s firing order

https://www.aa1car.com/library/misfire.htm

[Joshua Logsdon]

Thank you! Information like below was throwing me off when it talked about the code digits “correspond to the cylinder number in the engine’s firing order”. I don’t know if they are saying it correctly and it’s just the way I’m interpreting the info, but it had me thinking I needed to know the firing order to use the code and track down the actual cylinder. I’ll go by the code digit telling me which cylinder it is and then just making sure I know which cylinder is that digit.

The last two digits in the misfire code will tell you which cylinder or cylinders are misfiring. The digits correspond to the cylinder number in the engine’s firing order

https://www.aa1car.com/library/misfire.htm

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